Disclaimer: These characters and settings aren't mine.
At first Shikamaru had assumed that any sort relationship with Naruto would be too troublesome to pursue. Naruto made him distracted, made his brain hurt, made his hands shake, breath hitch, made him squirm. But Naruto had persisted, had battered away at his resolve and then crowed smugly when Shikamaru gave in. And then it happened a second time, then a third and a fourth...By the tenth time, Shikamaru was perfectly happy to oblige Naruto and had made a stern mental note not to assume anything that included the other boy.
Because what he has with Naruto is...comfortable, for lack of a better word. Naruto doesn't nag or whine; he doesn't expect Shikamaru to change. Best of all he doesn't ask Shikamaru if he thinks he's pretty (although when Sakura ambushed Naruto and forced clips in his hair to keep it down, Shikamaru thought he was quite pretty). What Naruto does do is ambush Shikamaru whenever the mood strikes him: training grounds, alleyways, Shikamaru's bedroom floor, etc. There was a memorable occasion in a corridor in the Hokage Tower and an even more memorable encounter on top of the Hokage monument.
Most of the time Shikamaru still finds Naruto troublesome. The other boy's energy makes him exhausted. Naruto's enthusiastic proclamations make his ears hurt and the bright clothing makes his eyes hurt as well. But when the clothing is thrown aside or pushed back, when Naruto's energy is focused on making Shikamaru come in an embarrassingly short amount of time, when Naruto's voice is low and moaning in Shikamaru's ears, he doesn't think he's troublesome. In fact he thinks he might actually love Naruto but that makes his head hurt more than Naruto ever could. So he pushes the thought away and arches up into the hard lines of Naruto's body.
He waits for one of them to make a mistake, waits for the one slip-up that will bring their happy bubble crashing to the ground, but it never comes. Naruto continues to ambush him with no regard as to whether it's convenient for Shikamaru or not (but Shikamaru would never say, could never say no, not to Naruto). And every time Naruto leaves him with a broad grin and the promise of again in his eyes. And the seasons slip away to the movement of their bodies.
Spring is when Ino marches up to Shikamaru with determination written in every line of her body. Shikamaru watches her approach with slight trepidation and wishes Naruto was there to get him out of whatever Ino wants. But Naruto never appears so Shikamaru just braces himself. His preparation turns out to have a purpose because when Ino promptly informs him that she knows he has a girlfriend, he almost has a heart attack. He tries to dissuade her with a few drawled words but he settles herself down next to him and lists all her reasons. Shikamaru just tunes her out and wonders if the fact that he can see various Naruto-related shapes in the clouds should be reason for alarm.
In the end he idly agrees with everything she says and in the very end he tells her his 'girlfriend' has dark hair and brown eyes - AKA, the majority of the female villagers. Momentarily satisfied, Ino prances off to collaborate with her equally scary friends about their next move and Shikamaru breathes easy for the rest of the morning.
That afternoon Naruto swings himself into Shikamaru's open bedroom window with none of the grace ninja should have. They exchange small chat for a little while in case Shikamaru's parents come to investigate the noise and somehow the topic of Ino comes up. When Shikamaru tells Naruto about the exchange between him and his teammate, the other boy immediately launches into a tirade. Shikamaru lets it go on for a few minutes before saying he knows Naruto's not a girl, he's had physical proof, remember? The comment is enough to make Naruto stop mid-sentence and stare at Shikamaru.
One minute later they're happily writhing together on Shikamaru's bedroom floor.
Four minutes later Shikamaru is poking Naruto in the direction of his bed. Naruto has worn him out so thoroughly that the only thought in his head is that he's not going to sleep on the floor. The possible negative outcomes of letting Naruto sleep (and just sleep) in his bed never feature in his mind.
When Shikamaru's flirting with the boundaries of sleep Naruto mumbles, "If you're going to call me a girl, you'd better get me chocolate next White Day." Shikamaru wants to point that he never actually called Naruto a girl but sleep gets the better of him.
They end up sleeping away the rest of the afternoon and that night, Shikamaru can't sleep. He ends up building a card mansion until four o'clock in the morning.
Summer finds them seeking sanctuary under the canopy of a tree older than they'll ever be. Shikamaru has the rough bark of the tree rubbing against his bare back and the unsettling feeling that there is a bug crawling over his foot. Naruto is straddling his lap and radiating heat like a furnace. The day's heat, plus the friction created by the slow slide of Naruto's body over his, leaves Shikamaru sweaty and overheated and in a state of pure discomfort. But he can't ask Naruto to stop, not when they're so close and Naruto's making noises like that.
The rest of summer passes in a similar state and by the end of it Shikamaru is ready to embrace autumn.
Autumn means there is clouds in the skies for him to watch. It means Naruto's body heat is less of a bother and he's not walking around drenched in sweat. Autumn means a slight decrease in the amount of missions he gets and he spends most of his time on his back at staring at the clouds.
Sometimes Naruto joins him and becomes a solid presence at Shikamaru's side. On the odd occasion that cloud watching doesn't lead to sex, Naruto sleeps. He drifts off with the faint sun on his face and the grass at his back. Often he curls up at Shikamaru's side and uses his stomach as a pillow and casts his body heat over both of them. Shikamaru doesn't mind though. In fact, he rather likes it.
He marvels at the amount of trust Naruto is placing in him. Like this - in a sleep so deep and relaxed - Naruto is at his most vulnerable and the both know it. For a ninja, such trust is difficult to give and Shikamaru is all too aware of how fragile it is. It makes him feel warm and fuzzy all over and he smiles idly at the sky. Time melts away as he cards his fingers through sunshine-bright hair and ponders what shape trust would take if it was an object.
And so autumn passes in a haze of drowsiness and sentimentality.
One winter's day finds them huddled under Shikamaru's sheets. Now Shikamaru is more than happy to have Naruto pressed against him and Naruto is more than happy to oblige. He doesn't like to do anything by half and sex is no exception - he's wrapped around Shikamaru like some kind of external parasite. The thought makes him laugh and it comes out brief and breathless. Naruto stills and looks at him with the beginnings of a scowl on his face so Shikamaru drags him down for a kiss.
Moments later they've both forgotten it.
A lot of winter is spent under the sheets. Shikamaru flaunts his intellect by designing alerts to place around his bedroom so that there's no chance of anyone sneaking up on them. His bedroom is the coldest in the house and he's never quite warm enough. But with Naruto there it's so much better. He presses against Shikamaru like he's trying to crawl inside his skin and offers only minimal protest when Shikamaru lays his freezing feet against his shins. Under the blankets they create their own bubble of heat and if Shikamaru is ever in a metaphoric mood he will say it is like their relationship.
When Naruto leaves his house (usually at nightfall) Shikamaru bundles up his sheets and dumps them in the corner of his room. Those nights he curls up on his bare mattress and basks in the lingering heat. In the morning he carts them downstairs and into the washing machine. When his father catches Shikamaru unloading them once clean, he gives his son a knowing smile. Shikamaru just thinks, 'you have no idea' and trudges upstairs with his clean linen.
Naruto bounds up to him on the last day of the year with a broad grin and a devious glint in his eyes. As he grabs Shikamaru's collar and drags him off to the nearest shadowed corner, Shikamaru stares at his back and realises that they're been doing this for over a year already. And just like that the gates open and all the thoughts come tumbling out. They clamber over each other, each demanding attention and it takes Naruto slithering against him - for once, all serpentine grace - to lock them away again. But one thought remains - a memory - and Shikamaru decides this one is worth keeping.
When they're near completion he mouths 'I think I love you' against Naruto's shoulder.
And Naruto cups his face and draws him into a kiss and it says everything they can't dare to.